/**
 * Copyright 2018 jianggujin (www.jianggujin.com).
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.jianggujin.codec;

import java.io.IOException;
import java.io.InputStream;
import java.util.zip.CRC32;

import com.jianggujin.codec.util.JCodecException;

/**
 * CRC32
 * 
 * @author jianggujin
 *
 */
public class JCRC32 {
   private static final int BUFFER_SIZE = 512;

   /**
    * 编码
    * 
    * @param data
    * @return
    */
   public static long encode(byte[] data) {
      CRC32 crc32 = new CRC32();
      crc32.update(data);
      return crc32.getValue();
   }

   /**
    * 编码
    * 
    * @param data
    * @return
    */
   public static long encode(InputStream data) {
      try {
         byte[] buffer = new byte[BUFFER_SIZE];
         int read = data.read(buffer, 0, BUFFER_SIZE);
         CRC32 crc32 = new CRC32();
         while (read > -1) {
            crc32.update(buffer, 0, read);
            read = data.read(buffer, 0, BUFFER_SIZE);
         }
         return crc32.getValue();
      } catch (IOException e) {
         throw new JCodecException(e);
      }
   }
}
